Eddy was the youngest of six children: boys Samuel Dow (1808), Albert (1810), and George Sullivan (1812), followed by girls Abigail Barnard (1816), Martha Smith (1819), and Mary Morse (1821).

[15] In 1836, when Eddy was about 14 to 15 years old, she moved with her family to the town of Sanbornton Bridge, New Hampshire, approximately twenty miles (32 km) north of Bow.

[19] Ernest Bates and John Dittemore write that Eddy was not able to attend Sanbornton Academy when the family first moved there but was required instead to start at the district school (in the same building) with the youngest girls.

Eddy had written in her autobiography in 1891 that she was 12 when this happened, and that she had discussed the idea of predestination with the pastor during the examination for her membership; this may have been an attempt to mirror the story of a 12-year-old Jesus in the Temple.

She had to make her way back to New Hampshire, 1,400 miles (2,300 km) by train and steamboat, where her only child George Washington Glover II was born on September 12 in her father's home.

[23][24] Her husband's death, the journey back, and the birth left her physically and mentally exhausted, and she ended up bedridden for months.

[27] Eddy's father Mark Baker remarried in 1850; his second wife Elizabeth Patterson Duncan (d. June 6, 1875) had been widowed twice, and had some property and income from her second marriage.

"[48] Biographer Gillian Gill has disagreed with other scholars arguing they "have flouted the evidence and shown willful bias in accusing Mrs. Eddy of owing her theory of healing to Quimby and of plagiarizing his unpublished work.

A contemporary account by the Lynn Reporter stated:[50] Mrs. Mary Patterson of Swampscott fell upon the ice near the corner of Market and Oxford Streets on Thursday evening and was severely injured.

Eddy would later credit her accident as her moment of spiritual revelation and the "falling apple" that led to her discovery of Christian Science.

She claimed that after rejecting the medicines offered to her by her doctor, she opened her Bible three days after her fall and returned to full health after reading of Jesus healing the sick.

[56] In regard to the deception, biographer Hugh Evelyn Wortham stated "Mrs. Eddy's followers explain it all as a pleasantry on her part to cure Mrs. Crosby of her credulous belief in spiritualism.

[64] According to Cather and Milmine, Richard Hazeltine attended seances at Clark's home, and Eddy had acted as a trance medium, claiming to channel the spirits of the Apostles.

[77][78] In 1881, Mary Baker Eddy started the Massachusetts Metaphysical College with a charter from the state which allowed her to grant degrees.

"[83] In 1879, she and her students established the Church of Christ, Scientist,[84] "to commemorate the word and works of our Master [Jesus], which should reinstate primitive Christianity and its lost element of healing.

[99][100] "Malicious animal magnetism", sometimes abbreviated as M.A.M., is what Catherine Albanese called "a Calvinist devil lurking beneath the metaphysical surface".

The McClure's biography spends a significant amount of time on malicious animal magnetism, which it uses to make the case that Eddy had paranoia.

[106][107] According to Gillian Gill, Eddy's experience with Richard Kennedy, one of her early students, was what led her to began her examination of malicious animal magnetism.

[114] Later, Eddy set up "watches" for her staff to pray about challenges facing the Christian Science movement and to handle animal magnetism which arose.

[115] Gill writes that Eddy got the term from the New Testament account of the garden of Gethsemane, where Jesus chastises his disciples for being unable to "watch" even for a short time; and that Eddy used it to refer to "a particularly vigilant and active form of prayer, a set period of time when specific people would put their thoughts toward God, review questions and problems of the day, and seek spiritual understanding.

[115] As time went on, Eddy tried to lessen the focus on animal magnetism within the movement, and she worked to clearly define it as unreality which only had power if one conceded to it.

[124] Damodar Singhal noted that whether or not Eddy was directly influenced by Hindu philosophy, "the echoes of Vedanta in [her] literature are often striking.

[128] Professor of religious studies John K. Simmons, citing Peel, argued that Eddy "gave the theory no real credence, at least in verifiable written form," but acknowledged British-Israelism "seemed to attract the turn-of-the-century metaphysical crowd.

[138] In 1907, the New York World sponsored a lawsuit, known as "The Next Friends suit", which journalist Erwin Canham described as "designed to wrest from [Eddy] and her trusted officials all control of her church and its activities.

[142] Psychiatrist Karl Menninger in his book The Human Mind (1927) cited Eddy's paranoid delusions about malicious animal magnetism as an example of a "schizoid personality".

[144] In 1983, psychologists Theodore Barber and Sheryl C. Wilson suggested that Eddy displayed traits of a fantasy prone personality.

[146] Psychopharmacologist Ronald K. Siegel has written that Eddy's lifelong secret morphine habit contributed to her development of "progressive paranoia".

[147] Eddy died of pneumonia on the evening of December 3, 1910, at her home at 400 Beacon Street, in the Chestnut Hill section of Newton, Massachusetts.

In 1921, on the 100th anniversary of Eddy's birth, a 100-ton (in rough) and 60–70 tons (hewn) pyramid with a 121 square foot (11.2 m2) footprint was dedicated on the site of her birthplace in Bow, New Hampshire.

[157] Several of Eddy's homes are owned and maintained as historic sites by the Longyear Museum and may be visited (the list below is arranged by date of her occupancy):[158]